Add boot configuration for autoreload when writing to the CP drive

docs/en/boot.md

@@ -23,6 +23,7 @@ bootcfg(
     sense: [microcontroller.Pin, digitalio.DigitalInOut],
     # optional:
     source: Optional[microcontroller.Pin, digitalio.DigitalInOut] = None,
+    autoreload: bool = True,
     boot_device: int = 0,
     cdc_console: bool = True,
     cdc_data: bool = False,
@@ -66,6 +67,13 @@ Common matrix and direct pin configurations (see also the examples below):
 |direct pin        |direct pin |`None`     |
 
 
+#### `autoreload`
+CircuitPython will automatically reload when any data or meta data is written to
+the CircuitPython drive.
+Certain operating systems tend to do that without asking; in that case
+`autoreload` can be disabled as a workaround.
+
+
 #### `boot_device`
 Boot HID device configuration for `usb_hid`, see the [`usb_hid` documentation](https://docs.circuitpython.org/en/latest/shared-bindings/usb_hid/index.html#usb_hid.enable)
 for details.

kmk/bootcfg.py

@@ -11,6 +11,7 @@
 def bootcfg(
     sense: [microcontroller.Pin, digitalio.DigitalInOut],
     source: Optional[microcontroller.Pin, digitalio.DigitalInOut] = None,
+    autoreload: bool = True,
     boot_device: int = 0,
     cdc_console: bool = True,
     cdc_data: bool = False,
@@ -38,9 +39,10 @@ def bootcfg(
         source.direction = digitalio.Direction.OUTPUT
         source.value = False
 
-    # sense pulled low -> skip boot configuration
-    if not sense.value:
-        return False
+    if not autoreload:
+        import supervisor
+
+        supervisor.runtime.autoreload = False
 
     # configure HID devices
     devices = []
@@ -84,6 +86,11 @@ def bootcfg(
 
         usb_cdc.enable(data=True)
 
+    # sense pulled low -> Skip boot configuration that may disable debug or
+    # rescue facilities.
+    if not sense.value:
+        return False
+
     # Entries for serial console (REPL) and storage are intentionally evaluated
     # last to ensure the board is debuggable, mountable and rescueable, in case
     # any of the previous code throws an exception.